Operation of AC Microgrids with PV Panels’ Output Power Curtailment for Minimizing the Use of Energy Storage

In this paper, a method for operating AC microgrids in both off-grid or standalone and grid-connected modes is proposed to minimize the use of energy storage by increasing the number of PV panels and curtailing their output power. When the intensity of daylight decreases, power is imported from the main grid through an AC/DC/AC converter or solid-state transformers in parallel to compensate for the shortage. By using a three-phase transformer in Δ-Y connection with Y’s neutral connected to its local grounding system, the effect of unbalanced loads on the AC microgrid is minimized. The AC microgrid is operated at a constant frequency with necessary reactive power compensation, and power qualities of both voltage and frequency can be ensured.